/* pipe.c */
#include <unistd.h>
#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#define MAX_DATA_LEN 256
#define DELAY_TIME 1
int main()
{
pid_t pid;
int pipe_fd[2];
char buf[MAX_DATA_LEN];
const char data[] = "Pipe Test Program";
int real_read, real_write;
memset((void*)buf, 0, sizeof(buf));
/* 创建管道 */
if (pipe(pipe_fd) < 0)
{
printf("pipe create error\n");
exit(1);
}
/* 创建一子进程 */
if ((pid = fork()) == 0)
{
/* 子进程关闭写描述符，并通过使子进程暂停1s等待父进程关闭相应的读描述符*/
close(pipe_fd[1]);
sleep(DELAY_TIME * 3);
/* 子进程读取管道内容 */
if ((real_read = read(pipe_fd[0], buf, MAX_DATA_LEN)) > 0)
{
printf("%d bytes read from the pipe is '%s'\n", real_read, buf);
}
/* 关闭子进程读描述符 */
close(pipe_fd[0]);
exit(0);
}
else if (pid > 0)
{
/* 父进程关闭读描述符，并通过使父进程暂停1s等待子进程关闭相应的写描述符*/
close(pipe_fd[0]);
sleep(DELAY_TIME);
if((real_write = write(pipe_fd[1], data, strlen(data))) != -1)
{
printf("Parent wrote %d bytes : '%s'\n", real_write, data);
}
/* 关闭父进程写描述符 */
close(pipe_fd[1]);
/* 收集子进程退出信息 */
waitpid(pid, NULL, 0);
exit(0);
}
}
